Wires and Clocks
The wires that connect electronic devices are assumed to be short circuits. This assumption is as common as it is devastatingly wrong. Wires are longer, narrower, and more densely packed than ever. Signals will not only be delayed in these wires but can also cross talk. And this is for signals, wires that carry supply, ground, and clock are even worse. All these special networks go to almost the entire circuit, facing an enormous capacitive load.